Suspension assembly with integral projections having a coating of elastic material

ABSTRACT

A head support assembly for a disk drive is comprised of a head suspension assembly connected to an actuator arm at one end and supporting a head at the other end, wherein a projection is formed on a flexure closely fixed on a thin-plate load beam, said projection projecting toward a disk surface and having a smooth surface. The projection is formed at a region somewhat close to the head supporting end from the hinge portion of the load beam. When shock is applied to the disk drive, bending occurs around the hinge portion of the load beam. During such bending, the projection having a smooth round surface is caused to contact the disk, whereby the disk surface is prevented from being damaged.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a disk storage device, and, moreparticularly, to a structure of a suspension assembly on one end ofwhich a magnetic head is mounted.

2. Description of the Prior Art

Recent magnetic disk drives are being reduced in size, moreparticularly, in thickness, and various measures are being taken toaccommodate such circumstances. They include, for example, reducing thesize of the structure of a load beam. The load beam is a supportstructure for the magnetic head, for mounting it on an actuator, and themounting structure for the magnetic head. A typical structure forsupporting the magnetic head comprises, as shown in FIG. 1, a mountplate 10 connected to an actuator arm, a load beam 12 coupled to themount plate 10, and a flexure 14 coupled to the load beam 12, whereinthe magnetic head is supported on the flexure 14 with a gimbalstructure. A signal line 16 from the head is fixed on the side of theload beam 12.

FIG. 2 shows an exploded view of the mount plate 10, the load beam 12,and the flexure 14. Each component is worked into the predeterminedshape, and then coupled and fixed to each other. The load beam 12 or theflexure 14 is manufactured under precise control on its material andthickness so as to provide predetermined mechanical characteristics suchas natural frequency and stiffness. The load beam and the flexure aretypically made of stainless steel. The mount plate 10 is coupled to theload beam 12 with welding at a plurality of welding points 18 shown inFIG. 1. The load beam 12 and the flexure 14 are also coupled by weldingat a plurality of welding points 19.

As the disk drive is made smaller and smaller, the clearance betweendisks is narrowed down. Accordingly, there is an increased possibilitythat a head assembly disposed between the disks will collide with thesurface of a disk due to some external impact or vibration. If the loadbeam or the flexure on the head mount contacts a disk surface, the disksurface may be damaged, leading to damage or loss of data. It isbelieved that, since the load beam or flexure is generally made ofstainless steel as described above, and a sharp edge is formed on suchstainless steel member, when the edge hits the disk surface, the disksurface tends to be easily scratched.

FIGS. 3 and 4 schematically show a variation of the load beam. The loadbeam is in the form of a thin plate, and is deformed as shown in FIG. 3or 4 under an external impact. Consequently, the edge of the load beam(31 in FIG. 3, and 41 in FIG. 4) collides with the disk surface, so thatthe disk surface may be damaged, leading to damage or loss of data.

The present invention is intended to provide a head support structurewhich can prevent damage on the disk surface which may be caused bycontact between the disk surface and the head assembly.

Furthermore, the present invention is intended to provide a disk drivewith excellent impact resistance without impairing its low profile.

SUMMARY OF THE INVENTION

To attain the above objects, a head support assembly for a disk driveaccording to the present invention comprises a head suspension assemblyconnected to an actuator arm at one end and supporting a head at theother end, wherein a projection is formed on a flexure closely fixed ona thin-plate load beam, said projection projecting toward a disk surfaceand having a smooth surface.

According to one aspect of the present invention, the projection isformed at the vicinity of a hinge portion of the load beam, but at aposition offset therefrom.

For a fuller understanding of the nature and advantages of the presentinvention, reference should be made to the following detaileddescription taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view showing the arrangement of a typical headsuspension assembly;

FIG. 2 is an exploded view of the typical head suspension assembly;

FIG. 3 is a view showing deformation of the typical load beam;

FIG. 4 is a view showing deformation of the typical head suspensionassembly;

FIG. 5 is a schematic view showing the arrangement of a head suspensionassembly according to the present invention;

FIG. 6 is a sectional view of the load beam of the present invention ata region where projections are formed; and

FIG. 7 is an enlarged sectional view of the load beam at a region wherethe projection is formed.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The suspension assembly according to the present invention is usuallyused for a storage disk drive known as a hard disk drive. The storagedisk drive comprises a storage disk, a motor for rotating the storagedisk, and a head stack assembly or actuator for reading or writinginformation from or to the storage disk. The head stack assemblycomprises a head suspension assembly, and a carriage for supporting thehead suspension assembly. The head suspension assembly comprises a headhaving a transducer, a suspension having a thin-plate load beam, and aflexure fixed on the load beam.

FIGS. 5 and 7 show an embodiment of the present invention. Referring toFIG. 5, there is shown a plan view of the head suspension assemblyaccording to the present invention. It consists of a mount plate 10 tobe coupled to the actuator arm, a load beam 12 coupled to the mountplate 10, and a flexure 14 coupled to the load beam 12. The magnetichead is supported on the flexure 14 with a gimbal support structure. Asignal line 16 from the head is fixed on the side of the load beam 12.The mount plate 10 is coupled to the load beam 12 with welding at aplurality of welding points 18. The load beam 12 and the flexure 14 arealso coupled by welding at a plurality of welding points 19.

The following is materials and thickness of respective components of thehead suspension assembly according to the present invention.

Mount plate 10: Stainless steel (SUS 304), 0.25 mm thick

Load beam 12: Stainless steel (SUS 304), 0.062 mm thick

Flexure 14: Stainless steel (SUS 304), 0.030 mm thick

FIG. 6 is a sectional view taken along line A-A′ in FIG. 5. It is anenlarged sectional view of the projection formed on the load beam.Referring to FIG. 5, the load beam 12 is coupled to the mount plate 10at one end, and supports the head at the other end. The hinge portion 45is located substantially at the center of these ends. When shock isexerted on the disk drive, bending as described with reference to FIG. 3or 4 occurs at the hinge portion 45 as the bending point.

The flexure of the present invention is formed with two projections 47at regions somewhat close to the head supporting end from the hingeportion 45. FIG. 6 shows section A-A′ where the projections are formed.As shown in FIG. 6, the projection 47 has a smooth round surface. Bymaking a portion of the load beam to contact the disk surface when theload beam is deformed by external shock the region where this projectionis formed, the edge of the load beam can be prevented from collidingwith the disk surface.

FIG. 6 shows an enlarged sectional view of the projection 47. In thisembodiment, the projection 47 is formed to have a radius 1.35 mm, and aheight 0.06 mm from the load beam. Such shape and size of the projectionis determined by taking into account the spacing between disks,stiffness of the load beam, and the location where the projection isformed. The projections 47 may be formed by plasticly deforming theflexure 45 with a stamping tool.

The projections 47 formed on the flexure 14 is arranged to become theregion contacting the disk due to deformation of the load beam when thedisk drive is subjected to external shock or the like. Since theprojection 47 has a gradual round surface, it does not scratch the disksurface even if it contacts the disk surface. In addition, contacting ofthe projection can prevent the edge of the load beam from contacting thedisk surface.

While damage on the disk surface can be avoided because the projectionhas a round surface, an alternative embodiment forms a coatingconsisting of elastic material such as resin or plastics on the surfaceof the projection in order to reduce shock on the disk.

In addition, as can be seen from the comparison between FIG. 5 showingthe embodiment of the present invention and FIG. 1 showing a prior art,in the embodiment of the present invention provided with the projection47, a welding point for the load beam 12 and the flexure 14 is notformed on the region where the projection 47 is formed. Accordingly, theflexure 14 is in a free state from the load beam 12 to the region wherethe projection 47 is provided. With such free arrangement, theprojection 47 is designed to be more easily close to the disk surfacethan the edge of the load beam when the load beam is deformed, wherebythe edge is prevented from collision.

In the head suspension assembly according to the present invention, evenif the load beam collides with the disk surface when it is deformed byexternal shock, the projection with smooth round surface formed on theflexure contacts the disk surface, whereby it can prevent the edge ofthe load beam from colliding with the disk, and effectively prevent datarecorded on the disk surface from being lost.

While the preferred embodiments of the present invention have beenillustrated in detail it should be apparent that modifications andadaptations to those embodiments may occur to one skilled in the artwithout departing from the scope of the present invention as set forthin the following claims.

We claim:
 1. A suspension system comprising: a load beam havinglongitudinal, lateral and vertical axes, the load beam having rear,hinge, and forward sections, all being located substantially along aline parallel to the longitudinal axis, the rear section for attachmentto a support member, and the hinge section located between the rear andforward sections, the hinge section having a central aperture surroundedby two legs; and a flexure member attached to the forward section of theload beam, the flexure member extending to an edge of the hinge section,the flexure having a flexible section having a head receiving sectionfor receiving a transducer head on a first side of the head receivingsection, the flexure member having at least two rounded projectionslocated along a line substantially parallel to the lateral axis andlocated proximate to the hinge section, such that the roundedprojections are located closer to the hinge section than to the headreceiving section, the rounded projections projecting substantiallyalong a line parallel to the vertical axis, the projections extendingfrom the same side of the flexure as the first side of the headreceiving section, wherein the projection is an integral plasticdeformation of the flexure, the projections having a coating of elasticmaterial.
 2. The system of claim 1, wherein the radius of theprojections is greater than the vertical distance which the projectionsextend from the surrounding flexure surface.
 3. The system of claim 1,further including said transducer head attached to the head receivingsection of the flexure.